Multidimensional Fragility Analysis of Earth Slopes under Pulse-Like Ground Motions

Abstract

Near-fault pulse-like ground motions (GMs), characterized by large-amplitude coherent velocity pulses, have been demonstrated to exhibit a stronger correlation with landslide occurrence than ordinary non-pulse-like GMs. Therefore, comprehensive research on seismic slope fragility is crucial in enhancing earthquake resistance and disaster reduction capabilities in near-fault areas. This study proposes an approach based on incremental dynamic analysis (IDA) to develop fragility functions with multiple vulnerability states for the slope, using both the factor of safety (FOS) and Newmark sliding displacement ( D N ) as damage indices. In IDA, a total of 28 high-quality ground-motion records, including 14 pulse-like and 14 non-pulse-like GMs, were selected and scaled by peak ground acceleration (PGA) to multiple intensity levels ranging from 0 to 0.6 g. The FOS and D N of the slope, along with the corresponding PGA and peak ground velocity, are extracted to construct IDA. Ultimately, the exceedance probabilities of different slope limit states under given pulse-like and non-pulse-like ground-motion intensities are obtained. The results demonstrate that it is essential to incorporate pulse-like GMs and conduct two-dimensional (2D) fragility analysis, as incorporating pulse-like GMs yields higher exceedance probabilities than non-pulse-like GMs at the same IM, and 2D fragility curves similarly produce higher probabilities compared with one-dimensional curves. An illustrative example is provided to demonstrate the application of the proposed approach in seismic slope fragility analysis.